I have commented before that water in the garden can involve quite a bit of work, be it still water, treated water or running water. And water has had us busy this week.
We have treated water – a swimming pool. Once that is up and running for the season, it doesn’t take much to keep it clean because we have a salt filter on a timer. We have still water – two pond features with goldfish and an historic mill wheel which serves as a bird bath. The problem with the mill wheel is that, without fish in it, the mosquitoes breed up within about three days so we have to drain it and replace the water often over summer. True, mosquitoes breed up anywhere there is still water, even in the bromeliads (and we have quite a few of those). But the mill wheel is close to our bedroom window so I blame that for the incursions of nasty, blood sucking critters in the night.
The goldfish ponds are relatively easy care. I go thorough a couple of times a year to scoop out the build-up of rotting detritus and to restrict the growth of the aquatic plants and we have to top them up with water in dry spells. The pond at the bottom of the sunken garden is too shallow so it evaporates quickly and we often get algae spreading that needs scooping out with a sieve but it is all pretty straightforward.
Running water – the stream in the park – is nowhere near as simple to maintain. This week, we admitted defeat and hired a digger. We haven’t put a digger through the stream for about 25 years and it is an absolute last resort because it destroys the entire eco-system. Generally, we can get away with going through with a long-handled rake and drainage fork every couple of years to haul out the excessive growth of choking weeds – back breaking work but kinder to the environment. This time it was beyond that and the issue was the excessive build up of silt. We were at the point where the stream was turning into a swamp with little water movement.
There were four reasons for this state of affairs and only one of those was caused by our management. The water that flows looks clean enough to the naked eye. As Mark observed, it is a good example of how a visual assessment is not an accurate guide to water quality. Because it flows through farmland upstream, the silt loading is high. It runs dirty every time it rains and and over the years, the silt dumped on our stretch had built up. It also carries a very high nutrient loading from farm runoff and that means we are battling water weeds all the time. Then when the culvert at the corner was replaced last summer, it involved earth works on our place and the soil was not compacted so there was a major collapse during a flood. That reduced the water flow through the park by at least 50% with the water going over the weir and down the flood channel instead. Digging out that silt bank blocking the stream was too big a job to do by hand.
The fourth problem was of our making. When we decided to manage the park as a meadow and reduce mowing to just twice a year, we also stopped strimming the banks of the stream. With the build-up of silt and the greatly reduced water flow, the grass had invaded the river and formed a mat that was too heavy to dig out by hand. Hence the digger. We can’t get a big digger in because of access restrictions and the placement of many trees and shrubs so Lloyd spent two days quietly and cautiously working his way round the areas that could be accessed safely from the cab of the little digger. Its reach is not long enough to scoop the two ponds we have so they remain an unresolved issue at this stage. We are thinking we want to create a channel for the water and turn the ponds into bog gardens but the details of how we manage that transition are not quite clear yet. Natural ponds are even harder to maintain than the stream and we think it is time to draw the line beneath having those.
Mark will probably plant trees to shade more of the stream. When water is shaded, it stops the rampant growth of choking water weeds and it is much easier to stand on the bank and rake out what is there.
I have a vested interest in this. I have found that it is easier to weed the stream by dropping the level (which we can do with the weir and the flood channel) and getting in the water to clear it. It is a very muddy procedure but easier on my back than doing it from the bank. I started doing this last week before we decided to get the digger. I cleared one stretch of several metres but I can never get in that water again. The next day, I was back again, this time raking from the bank just down from that area I had cleared. And lo, there was a very large eel undulating through the shallow water. I am always aware of my tendency to hyperbole so I didn’t want to exaggerate its size but Lloyd spotted it sunning itself the next day and estimated it to be about 80cm or more in length with a girth behind its head of close to 50cm in circumference. I knew we had eels. I had to head one in the right direction to get back in the stream and I have seen many small ones. But that is too large an eel for me and there may well be more than one of them that size. I am scared of eels.
The aim is to manage the stream without needing to resort to a digger again – at least in our lifetime.